Droplet Ejection Head Flow Resistance Design
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Solution Overview
Problem
Existing droplet ejection heads face challenges in simultaneously improving fluid cross-talk and refilling characteristics, particularly due to the difficulty in balancing flow channel resistance, nozzle diameter, and ink flow symmetry, which affects ejection frequency and stability.
Innovation Solution
A droplet ejection head design that sets specific relationships between the flow channel resistance of individual supply and recovery channels and nozzle diameter, with parallel common supply and recovery channels connected through droplet ejection units, ensuring symmetrical arrangements to distribute ink flow evenly and optimize refilling speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dampers are arranged inside the flow channels to suppress pressure variation transmission, then fluid cross-talk is reduced, but device complexity increases and density of ejection elements decreases
Solution Approach 1:
The invention extracts and eliminates the damper components from the flow channel structure. By setting the individual supply channel resistance to a specific range (1.0×10^13 to 1.0×10^14 Pa·s/m³), the system achieves fluid cross-talk suppression without requiring separate damper elements, thereby reducing device complexity while maintaining reliability.
Solution Approach 2:
The invention changes the resistance parameter of the individual supply channel to a specific range. This parameter adjustment serves dual purposes: suppressing fluid cross-talk by limiting pressure variation transmission and eliminating the need for additional damper structures, thus resolving the contradiction between reliability and device complexity.
2Reliability
If flow channels are restricted to suppress pressure variation transmission, then fluid cross-talk is reduced, but individual refilling characteristics deteriorate
Solution Approach 1:
The invention optimizes the individual supply channel resistance to a specific range (1.0×10^13 to 1.0×10^14 Pa·s/m³). This parameter setting achieves a balance: it restricts flow sufficiently to suppress fluid cross-talk while maintaining adequate refilling speed by not overly constraining the channel dimensions.
Solution Approach 2:
The invention applies partial restriction through controlled resistance rather than complete channel closure. By setting resistance within a specific range, the system achieves sufficient cross-talk suppression without excessive restriction that would harm refilling characteristics, implementing a moderate, optimized level of flow control.
3Speed
If nozzle diameter is increased to improve ink flow, then refilling speed increases, but fluid cross-talk increases due to higher pressure variation
Solution Approach 1:
The invention compensates for the effect of increased nozzle diameter by adjusting the individual supply channel resistance to a specific range. This resistance adjustment counteracts the increased pressure variation from larger nozzles, maintaining fluid cross-talk suppression while allowing larger nozzle diameters that improve refilling speed and ink flow.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively suppresses fluid cross-talk, stabilizes refilling, and enables high-frequency droplet ejection by distributing ink flow evenly across nozzles and adjusting refilling timing according to ejection frequency.
Implementation Method 1
the flow channel resistance R1 (Ns/m5) of the individual supply channel and a flow channel resistance R2 (Ns/m5) of the individual recovery channel
Data Source
AI summary
In a droplet ejection head, each of droplet ejection units includes: a nozzle which ejects droplets of liquid, a pressure chamber which is filled with the liquid and connected to the nozzle, a drive element which applies pressure to the liquid inside the pressure chamber, and an individual supply channel and an individual recovery channel which are connected to the pressure chamber. The liquid is supplied to and recovered from the pressure chamber through the individual supply channel and the individual recovery channel. In each of the droplet ejection units, a diameter Dn (μm) of the nozzle, a flow channel resistance R1 (Ns/m5) of the individual supply channel and a flow channel resistance R2 (Ns/m5) of the individual recovery channel satisfy:3.247×1015exp(−0.1717 Dn)≦R1≦3.278×1015exp(−0.1456 Dn);and3.247×1015exp(−0.1717 Dn)≦R2≦3.278×1015exp(−0.1456 Dn).